Extension scaffold jack



June 18, 1957 Filed Oct. 26, 1953 Fig.

G. D. FREEMAN,

EXTENSION scAFFoLD JACK 2 Sheets-Sheet 1 George D.. Freeman INVENTOR.

June 18, 1957 G. D. FREEMAN EXTENSION soAFFoLD JACK 2 Sheets-Sheet iledOct. 26. 1953 George D. Freeman INVENTOR WM my;

United States Patent O 2,796,299 EXTENSIoN scAFFo'LD JACK George D.Freeman, Alvin, Ill. Application October 26,1953, Serial No. 388,205

1 Claim. '(Cl. 3044-29) This invention relates to 'an extension scaffoldjack and more specifically provides 'a 'scaffold to be employed inconstruction work wherein 'the Yscaffold may be vertically adjustamewithout removing 'the scaffold boards and the various materials usuallydisposed'th'ere'o'n.

Anl object of this 'invention istq'provide van extension 'scaffold .jackhaving a plurality 'of suecess'ively extendable frame members which aretelescopic in relation to each other and including means for extendingthe frame, locking the frames in Yextended position and bracing the'frames in their extended position.

A 'furtherebjeet Aof this invention is .to provide a `neveu rack andpinion lifting means wherein the rack is sectional whereinsuccessive'se'ctions 'ofjth'e rack may be attached to the first sectionof the vrack thereby extending successive frame members. Y

A further VVob'jerc't yof this invention is to ,provide an Aextensionscaffold jack having a-d e tachable se'ction secured thereon and aplurality `of extensible frames with each of lt-he 'frames havingalignabl'e apertures therein 'and a rlocking pin extending therethrough"for :securing the 'frames in e'X- tended position.

Yet another object of this invention is to `provide an extensionscaffold jack which is simple in construction, sturdy and rugged innature, efficient to operate and constructed of 'readily 'obtainablematerials thereby lending itself to economicrnanufacture.

These together with` other objects Aand -advant'ageswhich will becomesubsequently apparent reside in ithe A'details fof construction andoperation as more :fully hereinafter described fand claimed, referencebeing had to fthe `accompanying drawings forming a part hereof, wherein"like numerals refer to like parts throughout, and in which:

Figure -1 is a `side View of 4the extension scaiiold jack -of thefinven't'ion Ain Yextended Aposition "with the uppermost member being adetachable extension;

Figure 2 is Va longitudinal, vertical section 'taken substantially'along the `center -line of the 'frame showing the details-oftheirack-and pinioneextension means;

Figure 3 -is'a transverse, vtop plan section taken substa`ntiallly alongsection line 3&3 of YFigure `1 s'howi'ngthe'rela- 'tionship of 'the rackandpi-nion |lifting means;

Figure l Iis fa side elevational `vi'ewo'f the extensionscaffold jack incollapsed position with the top extension removed therefrom;

Figure 5 is a detail perspective View showing one of the detachablesections of the rack;

Figure 6 is a detail top plan section taken substantially along sectionline 6-6 of Figure 4 showing details of the brace attaching means; and

Figure 7 is a detail section showing the projecting guide and the socketreceiving portion of the uppermost extension which is detachable fromthe uppermost frame.

Referring now specifically to the drawings in generell, it will be seenthat the numeral 10 generally designates the extension scaffold jack ofthis invention generally comprising a lower frame member 12, a secondframel member ICC 2 14, a third or upper frame member 16 and adetachable exten-sion frame member 18.

It 'will be seen that each ofthe 'frame members 12, 14, 1'6, and 18 isformed with a pair of vertical uprights and a pair of cross-braces 20and 22 being connected to opposite end 'portions of the uprights of theframes by suitable screw threaded members 2'4 having an operating handle26 thereon for ease of manipulation. The cross braces 20 and 22 aresecured at point 28 where the braces cross over each other. Each of theuprights of the frame members 12, 14, 16 and 18 is tubular with theilowermost frame 12 having a base member 30 secured to the lower Vend ofthe v tubular uprights forming a support and closure for the lower endof the uprights ofthe frame member 12.

As shown in Figure l, the frame 16 includes a crossmember 32 connectingthe upper ends of the vertical uprights of 'the frame members 16 'andforming a support for scaffold boards or lthe like. As shown in Figure7, the upper ends of the 'vertical uprights of the frame 16 are eachprovided with an upwardly `extending rod 34 with an enlarged ballvmember 36 on the end thereof 'and it will be seen that the ball member36 forms a guide and positioning means for the 'tubular uprights of theextension member 18 wherein the extension member or frame 18 'may 'beremoved from the upper frame member 16. A cross member is securedbetween the upper ends of the vertical uprights of the extension frame18 with the vertical uprights extending slightly beyond the cross-memberwherein scaffold boards will be retained on the cross- *member 38 inanobviousmanner.

A's will be seen in V'the drawings, the upper end of the verticaluprights of the lower frame member 1-2 andthe intermediate frame member14 and the lower ends of the upper'frame member 16 andthe intermediateframe member 14 are provided'with apertures 40 which are alignable witheach other when in --their extended position and lock- -ing pins 42 areprovided for Vinsertion in the aligned apertures when the frames `16, 14and 12 'are in extended position, thereby locking 'the frames in suchextended position. :lt will ibe understood that the brace members 20and-22 `on the frame 'member 14'may be removed, thereby lpermitting theuprights `of the frame 14 to be telescoped into the uprights of 'theframe 12 as the uprights of the frame :14 are 'smaller than the uprightsof the frame 12, vand it will 'be further `understood that the uprightsof the 'frame member 16 may Vbe telescoped .into the uprights of theframe member "14 after removal yof the brace Vmembers 20fand 22. Theextension frame 18 may be removed and the vdevice will be in itscollapsed position, as shown in vFigure-4.

It will be seen yin the drawings that a projecting lug member 44 Aisrigidly ysecured to the side of one of the vertical uprights of theupper frame member 16, and a depending elongated .member 46 is rigidlysecured to the undersurface thereof and extends downwardly parallel toVthe vertical upright of the frame 16 in spaced relation thereto. .Itwill be Lseen that vthe elongated member is provided with projectingteeth 48 along one side thereof and an aperture 50 is provided at itslower end for a purpose described hereinafter. It will be understoodthat the elongated member i6 with the teeth 48 thereon forms a rack.

A U-Shaped bracket member 52 is secured adjacent the upper `en-dof thevertical upright of the lower frame member 12 by suitable welding lorthe like and surrounding the elongated member 46. A spacer member S4 issecured to the outer circumference of the vertical upright of the frame12 and includes `a bearing portion 56 riding against the rear edge ofthe elongated member 46. A pinion gear 58 is journaled between the legsof the U- shaped member 52 `on a suitable axle 60 with one end of theaxle 60 projecting beyond the U-shaped member 3 52 and a handle 62 issecured to the projecting end of the axle 60. The pinion gear 58includes teeth 64 which are in meshing engament with the teeth 48 on theelongated rack 46. A gravity operated p-awl 66 is pivotally secured tothe inner side of one of the legs of the U- shaped member 52 adjacentthe upper edge thereof and engaging the teeth 64 of the pinion gear 58wherein the gear 58 may be rotated only upon disengagement of the pawl66 from the teeth 54. It will be seen that the bearing surface S6maintains the elongated rack 46 in correct position for meshing of thegears 48 and 64. As 4shown in Figure 1, a second section of rack,indicated by the numeral 68, may be secured to the rack member 46 byinsertion of a suitable fastener 70 through the aperture S in the rack46 and an aperture 72 in a projecting lug on the upper end of thesection 68. The

ra-ck section 68 is provided with an aperture at the bottom end thereoffor securing successive sections of elongated racks wherein each sectionis similar to the section 68, as shown in Figure 5, with each sectionhaving teeth 48 thereon. It will be understood that the successive framemembers 16, @14 and the like may be extended -by `attaching successivesections of the rack to the lower end of the first rack Section 46wherein the device has a long range of adjustability.

The operation of the device will be readily understood. The extensionscaffold jack 10 of this invention is in its normally collapsed positionin Figure 4, and by releasing 1 members 24. It will be seen that theycross-piece 32 may i be used to support a scaffold board thereon. Itwill be understood that additional sections 68 may be attached to theoriginal rack section 46 for extending the frames 16 and 14 to theiruppermost vertical positions in an obvious manner. If a greater verticalheight is required, the

extension frame 18 may be positioned over the upper frame 16 with thetubular uprights of the extension 18 extending over the guide bar 36 andthe extending shank 34 wherein the uprights of the frame 18 are inalignment with the frame 16 and supported thereon. The

vcross-member 38, like the cross-member 32, is adapted to hold a scaioldboard thereon and it will be noted that both of the cross-members 32 and38 are recessed below the upper ends of the vertical uprights of theframe members 16 and 18 wherein scaffold boards will be retained on thecross-members. Obviously, the device of this invention may `beconstructed of readily obtainable pipe or other tubular members whereinthe device will be economically feasible and the device may be utilizedwithout removing the scaffold boards and vertically adjustable withoutremoving the scaffold boards and the usual material found thereon. Thisis especially useful in masonry construction where there is usually aheavy load of building blocks, mortar or tools on the scaffold boardsand it is desirable to adjust the scaffold boards vertically withoutremoving the material on 'the boards. The locking pins 4-2 provide .alocking means for securing the frames in fully extended position and thepawl member 66 provides a lock for securing the frames in any extendedrelation.

From the foregoing, the construction and operation of the device will bereadily understood 1and further explana-tion is believed to beunnecessary. However, since numerous modifications and changes willreadily occur to those skilled in the art, i't is not desired to limitthe linvention to the exact yconstructionsh'own and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the appended claim.

What is claimed as new is as follows:

An extension scalold jack comprising a pair of tubular verticaluprights,brace means interconnecting said uprights, a plurality -of tubularextensible members telescopically received in each of said tubularuprights, a cross member rigidly connecting the upper ends of the upperpair of tubular extensible members, .an extensible rack member connectedat one end to one of said uppermost pair of tubular extensible membersand extending downwardly in spaced, parallel relationship thereto, abracket extending from one of said tubular vertical uprights, guidemeans in said bracket for said rack member, a gear journaled in saidbracket and having teeth in meshing engagement with the teeth of saidrack member, a handle attached to said gear for moving the rack andtubular extensible members upwardly with respect to the tubular verticaluprights, said extensible rack member beingl provided with a pluralityof detachable rack portions each suspended from a higher rack portion,each portion having a length substantially equal to the length of asingle tubular extensible member, and removable 'lock pins in saidtubular vertical uprights and lthe lowermost tubular extensible membersfor locking said tubular extensible members in upwardly moved position.

References Cited in the tile of this patent UNITED STATES PATENTS 60,085Tanner Nov. 27, 1866 382,245 Stadler 4May 1, 1888 417,678 MacLaurin Dec.17, 1889 831,994 Rudman Sept. 25, 1906 1,012,246 Clarke et al. Dec. 19,1911 1,084,966 Rodes Jan. 20, 1914 1,442,075 Knechtel Ian. 16, 1923 v1,725,329 Blandford Aug. 20, 1929 1,905,626 Hershey Apr. 25, 19332,062,473 Norton Dec. 1, 1936 2,290,450 Renschin July 21, 1942 2,311,988Lavn Feb. 23, 1943 2,472,887 Core June 14, 1949 2,546,674 North Mar. 27,1951 2,573,575 Keroson Oct. 30, 1951 2,672,319 Nelson Mar. 16, 1954

